Detectors of visible wavelength radiation and detectors of IR radiation are both well known in the art. One known material that is well-suited to fabricating visible wavelength detectors and associated circuitry is Silicon. IR detectors are typically fabricated from material selected from Group II-VI of the period table, such as Hg.sub.(1-x) Cd.sub.x Te, wherein x may vary within a range of approximately 0.2 for long wavelength IR (LWIR) to a value of approximately 0.4 for short wavelength IR (SWIR).
For some applications it may be desirable to provide both visible wavelength and IR radiation detectors for simultaneously viewing a scene that include a source of visible wavelength radiation and also a source of IR radiation. However, the fabrication of a detector or detectors, from one type of material, that is responsive to both sources of radiation is difficult to achieve. One such material is InSb, which is known to be useful for fabricating sensors that are sensitive in both the visible and the IR spectrums. However, this type of sensor cannot distinguish the resulting visible signals from the IR signals.
It is thus an object of the invention to provide an integrated detector that is responsive to visible wavelength radiation and also to IR radiation, and which provides outputs expressive of a magnitude of each type of radiation.
It is a further object of the invention to provide a hybrid visible/IR detector assembly having a single common optical aperture, the assembly furthermore providing output signals that are separately expressive of a magnitude of each type of radiation.
It is one further object of the invention to provide a hybrid detector that is responsive to visible wavelength radiation and also to at least two different wavelengths (two colors) of IR radiation, and which provides outputs expressive of a magnitude of radiation at the visible wavelength and at each of the IR wavelengths.